Method of casting



Patented Sept. 5, 1944 METHOD OF CASTING Herbert M. E. Heinicke, Elgin, Ill., assignor to Western Electric Company, IncorporatelLNew York, N. Y., a corporation of New York No Drawing. Application December 10, 1941, Serial No. 422,329 I 4 Claims.

This-invention relates'tov a method of casting and more particularly to a method ofcasting a copper silicon manganese alloy.

In the casting of certain alloys, wherein silicon or manganese are employed, it has been regarded as necessary to postpone the addition of the silicon or manganese until just prior to the pouring, the belief being that the silicon or manganese would be burned ofl if added earlier. these ingredients just prior to pouring has, however, caused boiling" in the mold and resulted in the formation of air pockets in the castings which render them unfit for certain uses.

An objectof the present invention is to provide an effective and efiicient method of reduc-' ing porosity in castings.

One embodiment of the invention contemplates adding metallic silicon and copper manganese to a melt of copper approximately one hour prior to the pouring thereof.

Other objects and advantages will be apparent from the following detailed description of an.

embodiment thereof.

In practicing this invention, a charge of approximately 1170 pounds of copper is placed in a standard induction furnace and brought to a temperature of 1900 Fahrenheit. At this point, 38 pounds of metallic silicon containing about 98% silicon and 42 pounds of copper manganese containing about 30% manganese are added to produce a total charge of 1250 pounds. A loss of about of one percent metallic silicon and copper manganese occurs prior to the pouring; thus a charge of this proportion will produce a final alloy composing approximately 3% silicon, 1% manganese, and the rest copper. The churning action of the metal in the furnace causes these ingredients to be thoroughly mixed. A covering I of charcoal is maintained on the charge,-and ,suflicient salt is added to keep the slag fairly thin. The heating of the charge is continued until it reaches a temperature of from 2230 to 2250 Fahrenheit, at which time it is poured. The metallic silicon and copper manganese are added at 1900 Fahrenheit because it has been found to take approximately one hour in'a standard induction furnace for the charge to be-heated Addin final alloy has been varied with satisfactory re-' sults as follows:

Per cent Manganese .55 to 1.35 Silicon 2.85 to 3.35

Balance copper.

To produce a copper silicon'manganese alloy of any particular proportion withinthis range, it is only necessary to add approximately of 1% more metallic silicon and copper manganese than is desired in the final alloy.

By adding metallic silicon and coppermanganese an Hour prior to the pouring, the tendency of the metal to boil in the mold on pouring is totally eliminated, and the porosity of the cast alloyissubstantially reduced. When employing this method, it has beenfound unnecessary to reject any castings although with methods previously employed, rejections were frequent.

A similar process has been successfully employed in casting manganese brass. Here again the manganese was added an hour prior to the pouring with greatly improved results and no serious loss of manganese.

It will be understood that the nature and embodiments of the inventionherein described are I merely illustrative and many changes and modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A process of making a copper alloy containing from .55% to 1.35% of manganese and 2.85% to 3.35% silicon which comprises heating the copper to a temperature of about 1900 F., adding the silicon and manganese an hour prior to reaching pouring temperature, and raising the metal to the pouring temperature.

2. A process of making a copper alloy containing from 55% to 1.35% of manganese and 2.85%

to 3.35% silicon which comprises heating the copper to a temperature of about 1900 F., chumfrom 1900 to the pouring temperature of 2250 Fahrenheit.

Contrary to metallurgical theory it has been found that this process does not result in undue ligible. It will be obvious that the proportions of is" ing the molten metal-as by heating in an induction furnace, adding the silicon and manganese, heating the metal to a temperature of about 2250 F. over a period of time sufiicient to cause .said. silicon and manganesev to alloy with the copper, and then casting the metal.

3. A process of-making a copper alloy containing from;.5 5% .to 1.35% of manganese and 2.85% to 3.35% silicon, which comprises heating the copper to a temperature of about 350 F. under the pouring temperature, adding the silicon and manganese at said temperature, raising the metal to 3.35% silicon, which comprises heating the copper to a temperature of about 1900" F., adding the silicon and manganese an hour prior to reaching pouring temperature, raising the metal to the 5 pouring temperature, and then casting the metal.

HERBERT M. E, HEINICKE. 

